I made a post, and after 5 minutes I edited it, before anyone read it.
I didn't place my bet as I didn't handed any coins to you, nor we had a verbal agreement.
Plus, I could have just edited the post by putting some offtopic, without you realizing I previously made a bet, which I didn't.
It's like going into those gambling houses to bet on some football matches... You take a ticket, write down what you want to play for, but the employee doesn't "validate" the ticket, and you eventually decide not to bet after all.
edit: ok, it wasn't 5 minutes... more like 15... but the point stands